Tiffany has lunch at a restaurant and the cost of her meal is $\$30.00$. She would like to leave a $15\%$ tip. What is her total bill including tip?
Solution: The tip amount is equal to $15\% \times \$30.00$ We can find the tip by first calculating a $10\%$ tip and a $5\%$ tip, and then adding those two numbers together. To calculate a $10\%$ tip, move the decimal point in $\$30.00$ one place to the left. $10\%$ $\times \$30.00$ $\$3.00$ To calculate a $5\%$ tip, divide the $10\%$ tip amount in half. $5\%$ $\times \$30.00 = $ $\$3.00$ $ \div 2 = $ $\$1.50$ Adding the two amounts together gives us $\$3.00$ $\$1.50 =$ $ \$4.50$ The cost of the meal plus the amount of the tip will equal the total bill amount. $\$30.00 + \$4.50 = $ $\$34.50$ The total cost of the bill is $\$34.50$.